Average - General Questions

What is the average of the first 51 even numbers?

The average marks of a class of 43 students is 49 and that of another class of 35 students is 42. What is the average of all the students together?

A batsman has a certain average after 12 innings. In the 13th innings he scores 97 runs and thereby increases his average by 4. What is his average after the 13th innings?

What is the average of the first 50 odd numbers?

The average weight of 9 persons increases by 2.5 kg when a new person replaces one of them weighing 49 kg. What is the weight of the new person?